AITA for making fun of my brother's memorial for my deceased girlfriend?

Hello, yes I have a deceased girlfriend, she drowned last year, and I'm still not over it. She had a best friend with whom she shared a group chat with me, and we've all been supporting each other through this. They have always been best friends, and she's also been through a lot, so I want to note that it's not purposefully malicious, but the memorial she made for my girlfriend isn't really something I agree with.<br><br>For my girlfriend's memorial, her best friend made a shadowbox with my girlfriend's hair in it. I specifically did not want any of her hair, her teeth, her shoes, or anything inside the shadowbox, and I made that very clear to my girlfriend's best friend, so she put it in her own house, and gave it to my mom to give to me unopened.<br><br>I'm not exaggerating, my brother immediately ripped it open, emptied it in our backyard, set it on fire, and then threw the shadowbox itself in the garbage disposal and turned it on. I was not happy, and I yelled at him, calling him an asshole and a prick, and my parents are saying that I'm the asshole because he was "protecting" me from something I didn't want, so,<br><br>AITA?